The present invention relates to a volatile component detector.
In the food industry, in the process for the manufacture of foodstuffs in which emphasis is placed on the odor and the freshness and other qualities of foodstuffs, judgments as to quality as determinable by the relationship with odor have been conventionally performed by the human sense of smell. However, by this method, it is difficult to obtain precise data because of individual differences in the sense of smell, and quantitative data could not be obtained.
Recently, there has been the development of gas sensors and odor sensors that use voltage changes or current resistance values to detect when odor components having volatile components attach to them, and these have been used in detection apparatus that enables an objective assessment of the concentration of odor by the analysis of these changes in the status. It is therefore possible to promptly obtain accurate odor data (see, for example, Japanese Patent Laid-Open Publication No. 222154/1987, Japanese Patent Laid-Open Publication No. 259250/1989, and Japanese Utility Model Laid-Open Publication No. 156871/1987).
However, in a detection apparatus using a conventional odor sensor, as shown in outline in FIG. 12 for example, the odor sensor S is disposed so as to face a surface inside a detection chamber 2 of a detector 1 that is formed of a material such as stainless steel, for example, for which the attachment of odor is difficult. A sample for which the odor is to be detected is placed in a sample receptacle 3 inside the detection chamber 2, the door 4 of the detection chamber 2 is closed and the volatile components dispersed from the sample fill inside the detection chamber 2 were they are detected by the odor sensor S to therefore allow the detection of the concentration of the volatile components or their identification. When the odor molecules given off by the sample came into contact with the sensor S, the electrical resistance changes downwardly immediately and the current flowing through the circuit changes. This current is then converted into a voltage, amplified, and its value is displayed by the digital indicator, and printed by the printer.
In such a conventional detector, the structure is such that the sample for which the odor is to be detected is placed in a sample receptacle which is placed into and taken out of the detection chamber. Therefore, this necessitates the provision of an opening portion having a size which is large enough for a hand to reach into the detection chamber. Because of this, the volume of the detection chamber becomes larger and it takes a long time for volatile components dispersed from the sample to fill inside the detection chamber. The result is that a long time is taken for detection. In addition, it is also necessary to replace the air inside the detection chamber with odorless air so that the following detection can be performed but residual odor from the previous detection remains inside the detection chamber if the detection chamber is large, and this causes the problem of the residual odor influencing the accuracy of the data of the following odor detection. Even if activated charcoal is used as a deodorizing agent, it requires approximately one day for the residual odor to be completely removed, and therefore the efficiency is poor. Not only this, since there are no standards for judging whether or not complete deodorization has been achieved, it is easy for errors to occur in the following detection. Moreover, it is not sufficient to use a material such as Teflon (registered trademark}to which it is difficult for odors to attach, as the material for the detection chamber, since if there is a portion to which odor from a previous measurement still remains, then it will be impossible for this not to influence the following measurement. In addition, the odor will enter the detection chamber even if repeated measurement is performed for the same odor and this will become a cause of scattering in the measurement results with respect to the actual concentration. Accordingly, in delicate measurements where the identification of odors has to be performed, there has been the problem of sufficient accuracy being unobtainable.
In the light of these problems, the present invention has as an object the provision of a volatile component detection apparatus that has the number of parts in the configuration between the odor sensor and a sample receptacle that can be easily returned to an odorless state, that has an extremely small amount of residual odor that influences following measurements, that takes a short time to be deodorized after a measurement, and that can promote the efficiency of the measurement task.